Purpose: The purpose of this study is to evaluate the mechanical properties of a fracture resistant, resin CAD-CAM block. Method: An experimental fracture resistant composite (Kerr Exp), containing short-cut reinforcing fiber was tested along with current products, Paradigm MZ 100 (P MZ100) and porcelains E Max CAD, IPS E CAD. Flexural strength (FS), flexural modulus (FM), fracture toughness (K1C) were measured (5 specimens) according to IADR Abst.# 288, 2000. The means and (s.d.) were reported and the data were analyzed by anova ( p<0.05) to determine any significant difference between the means. Results: The data are reported in the table. The flexural strength of E Max CAD was significantly higher, followed by Kerr Exp., which was not significantly higher than the remaining materials. The elastic modulus of the materials was ranked: E Max CAD>IPS E CAD>P MZ 100>Kerr Exp. The fracture toughness of E Max CAD and Kerr Exp were not significantly different, but were significantly higher than the others. Conclusion: Kerr Exp. exhibited a high fracture toughness similar to E Max CAD. E Max CAD also exhibited a high flexural strength. The other mechanical properties were similar to other composites relative to conventional porcelains (supported by Kerr Corp.).
Material | FS | FM | K1C |
| MPa (s.d.) | MPa, (s.d.) | MPa m1/2 (s.d.) |
E.Max CAD | 257 (44)a | 81 (3.3)a | 2.59 (0.27)a |
IPS E CAD | 141 (10)b,c | 57.6 (2.6)b | 1.09 (0.25)c |
P MZ100 | 153.7 (23.6)b,c | 17 (0.8)c | 1.55 (0.23)c |
Kerr Exp | 171.4 (15.6)b | 10 (0.3)d | 2.39 (0.56)a,b |
*Different superscript letters in columns are significantly different.